Cytogenetic and molecular genetic studies of follicular and papillary thyroid cancers.

Cytogenetic studies have shown frequent clonal abnormalities in papillary carcinoma (PTC) and follicular carcinoma (FTC). Loss of heterozygosity (LOH) may suggest the presence of tumor suppressor genes and has not been reported in these neoplasms. These studies were undertaken to determine if consistent chromosomal abnormalities are associated with thyroid cancer, to determine likely regions for molecular genetic investigations, and to determine if there is allelic loss in thyroid tumors. Cytogenetic analysis of 26 PTC and 5 FTC showed clonal abnormalities in 9 and included -Y, +5, or inv(10)(q11.2q21.2) in PTC, and -Y or near haploidy in FTC. Using DNA probes specific for chromosomes 1, 3, 10, 16, and 17, we carried out restriction fragment length polymorphism analysis on 6 FTC, 3 follicular adenomas (FA), and 12 PTC. LOH of all informative loci on chromosome 3p was observed in all 6 FTC, but not in FA or PTC. No LOH was observed for loci mapped to chromosome 10 in PTC. Our results suggest: cytogenetic abnormalities of chromosome 10q are associated with PTC; cytogenetic and molecular abnormalities of chromosome 3 are associated with FTC; and a tumor suppressor gene may be present on the short arm of chromosome 3 important for the development or progression of FTC.

Loss of heterozygosity suggests multiple genetic alterations in pheochromocytomas and medullary thyroid carcinomas.

Loss of heterozygosity (LOH) at specific loci may help localize tumor suppressor genes involved in the formation of various familial and sporadic tumors. In addition, the genetic loci for a number of familial tumor syndromes have been mapped by linkage analysis. To explore the possible role of tumor suppressor genes in endocrine tumors, we tested 41 pheochromocytomas (34 sporadic and 7 familial) and 11 medullary thyroid cancers (MTC) (10 sporadic and 1 familial) for LOH near a variety of potentially important genetic loci: (a) the multiple endocrine neoplasia type 2A (MEN 2A) locus on chromosome 10; (b) the von Hippel-Lindau locus on 3p; and (c) the p53 and neurofibromatosis 1 loci on 17. We also examined chromosomes 1p and 22q because previous studies in a small number of pheochromocytomas and MTCs suggested LOH in these regions. Background rates for LOH were assessed using several "random" probes. Finally, we examined a number of clinical and histologic characteristics of these tumors for possible correlations with specific genetic alterations. LOH in the region of the MEN 2A locus was uncommon (0% for MTCs, 5% for pheochromocytomas). However, we found significant allelic losses in pheochromocytomas on chromosomes 1p (42%), 3p (16%), 17p (24%), and 22q (31%). We also noted a correlation between LOH on 1p and urinary excretion of metanephrine by these patients (P = 0.02). LOH on 1p, 3p, and 17p also appeared to be associated with increased tumor volume. Analysis of the smaller number of MTCs demonstrated allelic losses on chromosomes 1p and 22q. Our results suggest that tumor formation and/or progression in pheochromocytomas and MTCs involves multiple genes, analogous with the model proposed for colon carcinoma.

Efficacy of bilateral prophylactic mastectomy in BRCA1 and BRCA2 gene mutation carriers.

BACKGROUND: In women with a family history of breast cancer, bilateral prophylactic mastectomy is associated with a decreased risk of subsequent breast cancer of approximately 90%. We examined the association between bilateral prophylactic mastectomy and breast cancer risk in women at high risk for breast cancer who also had mutations in BRCA1 and BRCA2 genes. METHODS: We obtained blood samples from 176 of the 214 high-risk women who participated in our previous retrospective cohort study of bilateral prophylactic mastectomy. We used conformation-sensitive gel electrophoresis and direct sequence analysis of the blood specimens to identify women with mutations in BRCA1 and BRCA2. The carriers' probabilities of developing breast cancer were estimated from two different penetrance models. RESULTS: We identified 26 women with an alteration in BRCA1 or BRCA2. Eighteen of the mutations were considered to be deleterious and eight to be of uncertain clinical significance. None of the 26 women has developed breast cancer after a median of 13.4 years of follow-up (range, 5.8-28.5 years). Three of the 214 women are known to have developed a breast cancer after prophylactic mastectomy. For two of these women, BRCA1 and BRCA2 screening was negative, and no blood specimen was available for the third. Estimations of the effectiveness of prophylactic mastectomy were performed, considering this woman as both a mutation carrier and a noncarrier. These calculations predicted that six to nine breast cancers should have developed among the mutation carriers, which translates into a risk reduction, after bilateral prophylactic mastectomy, of 89.5%-100% (95% confidence interval = 41.4% to 100%). CONCLUSIONS: Prophylactic mastectomy is associated with a substantial reduction in the incidence of subsequent breast cancer not only in women identified as being at high risk on the basis of a family history of breast cancer but also in known BRCA1 or BRCA2 mutation carriers.

Differential loss of heterozygosity at 7q31.2 in follicular and papillary thyroid tumors.

We analysed 42 differentiated thyroid tumors including 15 follicular adenomas (FA), 13 papillary thyroid cancers (PTC) and 14 follicular thyroid carcinomas (FTC) with 13 microsatellite markers specific for the long arm of human chromosome 7 within 7q31; this region is deleted frequently in several other tumor types. Overall, 20 of the 42 samples analysed (48%) displayed LOH with one or more of the markers tested. LOH was detected most frequently (78%) in FTC, the most malignant of the thyroid tumors. A smallest common deleted region (SCDR) was defined in this tumor type flanked by markers D7S480 and D7S490. This SCDR is distinct from D7S522, the most commonly deleted locus in many other tumors, which was deleted in only one FTC. D7S522 did show LOH in two of six informative PTCs. None of the PTC and only two of the FAs showed LOH in the FTC SCDR. Since FA is considered a premalignant stage of FTC, our results suggest that inactivation of a putative tumor suppressor at 7q31.2 may be acquired during adenoma to carcinoma progression. The absence of LOH at this locus amongst PTC suggests that inactivation of this tumor suppressor is specific for FTC. In conclusion, LOH at 7q31 is a frequent event in differentiated thyroid cancer, and we have defined a 2 cM SCDR specific for FTC.

DNA ploidy and percent S-phase as prognostic factors in node-positive breast cancer: results from patients enrolled in two prospective randomized trials.

PURPOSE AND METHODS: To help clarify the clinical utility of flow-cytometric parameters, we performed flow cytometry on archival paraffin-embedded primary breast cancers from 502 patients treated on two adjuvant chemotherapy protocols performed by the North Central Cancer Treatment Group (NCCTG) and Mayo Clinic. DNA ploidy and percent S-phase (%S) were examined in univariate and Cox model multivariate analyses along with tumor size, menopausal and estrogen receptor status, Quetelet's index (QI), number of positive nodes and nodes examined, and Fisher and nuclear grades. RESULTS: Ploidy analysis showed that 40% of tumors were DNA diploid and 60% were DNA nondiploid (12% tetraploid and 48% aneuploid). There was no difference in relapse-free survival (RFS) (P = .82) or overall survival (OS) (P = .78) between the ploidy groups. Tetraploid patients had the longest RFS and OS of any group, but this did not achieve statistical significance. The %S was computed in 98% of cases and the medians were 9.0% for all patients, 6.4% for diploid patients, and 11.7% for nondiploid patients (P < .0001). By use of a %S greater than 12.3 as a prognostic variable in a univariate analysis, there was a significant difference in the RFS (P = .02) and OS (P = .007) of patients with low- versus high-proliferative tumors. However, when the %S was adjusted for clinical characteristics in the multivariate analysis, it was not a significant factor for RFS (P = .23) or OS (P = .36). CONCLUSION: These results indicate that DNA content and %S measurements by flow cytometry are not clinically useful independent prognostic factors in women with resected node-positive breast cancer administered adjuvant chemotherapy.

Sentinel lymph node biopsy with metastasis: can axillary dissection be avoided in some patients with breast cancer?

PURPOSE: Recent studies have suggested that the sentinel lymph node (SLN) biopsy is an accurate alternative staging procedure for women with breast cancer. The goal of this study was to identify a subset of breast cancer patients in whom metastatic disease was confined only to the SLN. MATERIALS AND METHODS: From two institutions, we recruited 222 women with breast cancer for SLN biopsy. A SLN biopsy was performed in each patient, followed by an axillary dissection in 182 patients. Histologic and immunohistochemical cytokeratin stains were used on all SLNs. RESULTS: The SLN was identified in 220 (97. 8%) of the 225 biopsies. Evidence of metastatic breast cancer in the SLN was found in 60 (27.0%) of the 222 patients. Of these patients, 32 (53.3%) had evidence of tumor in the SLN only. By multivariate analysis, two factors were found to be significantly associated with a higher likelihood of tumor involvement in the non-SLNs: primary tumor size larger than 2.0 cm (P =.0004) and macrometastasis (> 2.0 mm) in the SLN (P =.002). Additional analysis revealed that none (0%; 95% confidence interval, 0% to 18.5%) of the 18 patients with primary tumors < or = 2.0 cm and micrometastasis to the SLN had remaining axillary lymph node involvement. CONCLUSION: The primary tumor size and metastasis size in the SLN are independent factors in predicting the incidence of tumor in the non-SLNs. Therefore, the SLN biopsy alone may be adequate for staging and/or therapy decision making in patients with primary breast tumors < or = 2.0 cm and micrometastasis in the SLN.

Efficacy of contralateral prophylactic mastectomy in women with a personal and family history of breast cancer.

PURPOSE: To estimate the efficacy of contralateral prophylactic mastectomy in women with a personal and family history of breast cancer. PATIENTS AND METHODS: We followed the course of 745 women with a first breast cancer and a family history of breast and/or ovarian cancer who underwent contralateral prophylactic mastectomy at the Mayo Clinic between 1960 and 1993. Family history information and cancer follow-up information were obtained from the medical record, a study-specific questionnaire, and telephone follow-up. Life-tables for contralateral breast cancers, which consider age at first breast cancer, current age, and type of family history, were used to calculate the number of breast cancers expected in our cohort had they not had a prophylactic mastectomy. RESULTS: Of the 745 women in our cohort, 388 were premenopausal (age < 50 years) and 357 were post- menopausal. Eight women developed a contralateral breast cancer. Six events were observed among the premenopausal women, compared with 106.2 predicted, resulting in a risk reduction of 94.4% (95% confidence interval [CI], 87.7% to 97.9%). For the 357 postmenopausal women, 50.3 contralateral breast cancers were predicted, whereas only two were observed, representing a 96.0% risk reduction (95% CI, 85.6% to 99.5%). CONCLUSION: The incidence of contralateral breast cancer seems to be reduced significantly after contralateral prophylactic mastectomy in women with a personal and family history of breast cancer.

Insulinoma in a patient with NIDDM.

OBJECTIVE: To confirm insulinoma as the cause of hypoglycemia in a patient with NIDDM and determine the frequency of the co-occurrence of these two conditions. RESEARCH DESIGN AND METHODS: The patient underwent an in-hospital prolonged fast (< or = 72 h), according to standard protocol, and an ultrasound examination of the pancreas. All cases of histologically confirmed insulinoma at this institution over the period of 1927-1992 were reviewed to determine the prevalence of pre-existent diabetes mellitus. RESULTS: After 10 h of fasting, plasma glucose was low (1.89 mM); plasma insulin (258 pM) and C-peptide (1.39 nM) were elevated in the absence of sulfonylurea in the plasma. An insulinoma detected by ultrasonography was removed surgically with subsequent reoccurrence of insulin-requiring diabetes. Among 313 cases of insulinoma confirmed at this institution, this patient is the only one with pre-existent diabetes mellitus. CONCLUSIONS: Insulinoma occurs extraordinarily rarely in patients with pre-existing NIDDM.

Germline polymorphism of codon 727 of human thyroid-stimulating hormone receptor is associated with toxic multinodular goiter.

Toxic multinodular goiter (TMNG) represents a frequent cause of endogenous hyperthyroidism, affecting 5-15% of such patients (with higher frequencies reported in iodine-deficient areas of the world). Although mutations of human TSH receptor (hTSHR) have been described in autonomously functioning thyroid nodules (AFTN), the role of such mutations in the pathogenesis of TMNG remains unclear. To search for alterations of hTSHR in AFTN and TMNG, we performed bidirectional, dye primer automated fluorescent DNA sequencing of the entire transmembrane domain and cytoplasmic tail of hTSHR (TMD+CT-hTSHR) using DNA extracted from nodular regions of 24 patients with TMNG and 7 patients with AFTN. Eight of the 24 patients (33.3%) showed heterozygote polymorphism of codon 727 on the cytoplasmic tail of hTSHR with an amino acid substitution of aspartic acid to glutamic acid. Three of 24 (12.5%) patients with TMNG were found to carry a heterozygote mutation of codon 703, resulting in substitution of alanine with glycine. One patient had multiple heterozygote mutations including I606M (Ile to Met), A703G (Ala to Gly), Q720E (Gln to Glu), and D727E (Asp to Glu). Two patients exhibited silent polymorphism of codons 460 and 618. We found no mutation of the TMD+CT-hTSHR in 7 patients with AFTN, except for a silent polymorphism of codon 460 in 1. DNA fingerprinting of codon 727 using restriction enzyme NlaIII and genomic DNA confirmed the sequencing results in all cases, indicating that the sequence alterations were not somatic in nature. This technique was also used to examine peripheral blood genomic DNA from 52 normal individuals and 49 patients with Graves' disease; 33.3% of TMNG (P = 0.019 vs. normal subjects), 16.3% of Graves' disease patients (P = 0.10 vs. normal subjects), and 9.6% of normal individuals were heterozygous for the D727E polymorphism. Expression of the D727E hTSHR variant in eukaryotic cells (COS-7) resulted in an exaggerated cAMP response to TSH stimulation compared to that of the wild-type hTSHR. These findings indicate that a germline polymorphism of codon D727E of hTSHR is associated with TMNG, suggesting that its presence is an important predisposing genetic factor in the pathogenesis of TMNG.

Noninsulinoma pancreatogenous hypoglycemia: a novel syndrome of hyperinsulinemic hypoglycemia in adults independent of mutations in Kir6.2 and SUR1 genes.

In adults, endogenous hyperinsulinemic hypoglycemia is almost invariably due to insulinoma. In these patients with insulinoma, neuroglycopenic episodes exclusively after meal ingestion and negative 72-h fasts are extraordinarily rare. We describe five adults with neuroglycopenic episodes from hyperinsulinemic hypoglycemia within 4 h of meal ingestion and negative 72-h fasts. Each had negative transabdominal ultrasonography, spiral computed tomographic scanning, and celiac axis angiography of the pancreas. However, all showed positive selective arterial calcium stimulation tests indicative of pancreatic beta-cell hyperfunction. At pancreatic exploration, no insulinoma was detected by intraoperative ultrasonography and complete mobilization and palpation of the pancreas. Moreover, the resected pancreata showed islet hypertrophy and nesidioblastosis, but no insulinoma. No definite disease-causing mutation was detected in Kir6.2 and SUR1 genes, which encode the subunits of the pancreatic ATP-sensitive potassium channel responsible for glucose-induced insulin secretion. Four patients who underwent gradient-guided partial pancreatectomy have been free of hypoglycemic symptoms for up to 3 yr follow-up; the other, who underwent a limited distal pancreatectomy, has had brief recurrence of symptoms. The unique clinical features and responses to dynamic testing in these adults with hyperinsulinemic hypoglycemia in the absence of insulinoma may constitute a new syndrome of postprandial hypoglycemia from diffuse beta-cell hyperfunction.

Benign paragangliomas: clinical presentation and treatment outcomes in 236 patients.

Paragangliomas are rare tumors that arise from extraadrenal chromaffin cells. We examined the clinical characteristics, location, treatment, and outcome of 236 patients (141 females, 60%) with 297 benign paragangliomas evaluated at the Mayo Clinic during 1978-1998. The mean age (+/-SD) at diagnosis was 47 +/- 16 yr. Of the 297 paragangliomas, 205 were in the head and neck region, and 92 were below the neck. Paragangliomas were discovered and diagnosed incidentally on imaging studies in 9% of patients. Biochemical screening was performed in 128 patients; 40 patients (17% of the total and 31% of those screened) had hyperfunctional tumors. Of the 40 patients with tumoral catecholamine excess, 38 had documented hypertension. In patients identified with catecholamine-secreting paragangliomas, the sensitivities achieved by measurements in the 24-h urine collection were 74% for total metanephrines, 84% for norepinephrine, 18% for dopamine, and 14% for epinephrine. Multiple imaging modalities were used for tumor localization. The false negative rates were 0% for magnetic resonance imaging, 5.8% for computed tomography, 3.4% for angiography, 10.7% for ultrasonography, and 39% for radioactive iodine-labeled metaiodobenzylguanidine scintigraphy. Of 192 patients (81.4%) with follow-up data (mean, 43.9 months; range, 0.5-240), operative cure was achieved in 133 (69%). Of the 59 patients without cure, 23 had persistent disease, 5 had recurrent disease, 16 had multiple persistent synchronous tumors, and 15 subsequently developed metachronous tumors. In conclusion, most paragangliomas are nonhypersecretory and located in the head and neck region. Magnetic resonance imaging was associated with the lowest false negative rate, and metaiodobenzylguanidine was the least sensitive imaging study. A significant proportion of patients (31%) has persistent or recurrent disease, and long-term follow-up is important.

Laparoscopic adrenalectomy for adrenocorticotropin-dependent Cushing's syndrome.

Bilateral adrenalectomy is indicated for the treatment of ACTH-dependent Cushing's syndrome when the tumorous source of ACTH hypersecretion cannot be identified or removed. Potential advantages of laparoscopic over open adrenalectomy include shorter hospitalization, decreased requirement for postoperative analgesia, and decreased postoperative morbidity due to incisional complications. Bilateral laparoscopic adrenalectomy performed for the treatment of ACTH-dependent Cushing's syndrome was attempted in 19 patients at our institution between 1995 and 1998. Conversion to an open procedure was required in three patients. All patients who underwent bilateral laparoscopic adrenalectomy were subsequently followed to assess the outcome of this intervention. Twelve patients with pituitary-dependent Cushing's syndrome and four with ectopic ACTH syndrome underwent successful bilateral laparoscopic adrenalectomy. All patients experienced resolution of the signs and symptoms (e.g. proximal myopathy, hirsutism, and emotional lability) of Cushing's syndrome as well as weight loss, improved glucose tolerance, and improved control of blood pressure. No residual cortisol secretion was detected in the patients. Bilateral laparoscopic adrenalectomy is a safe and effective treatment for Cushing's syndrome when the ACTH-secreting neoplasm cannot be removed.

Frequent loss of heterozygosity on chromosomes 3p and 17p without VHL or p53 mutations suggests involvement of unidentified tumor suppressor genes in follicular thyroid carcinoma.

Follicular thyroid carcinoma (FTC) exhibits frequent loss of heterozygosity (LOH) on chromosomes 10q and 3p, suggesting involvement of tumor suppressor genes. We screened 14 FTC (10 Hurthle cell carcinomas and 4 nonoxyphilic FTC), 14 papillary thyroid carcinomas, and 7 follicular adenomas for LOH on chromosome arms 1p, 3p, 3q, 10p, 10q, 11p, 11q, 13q, 17p, and 17q. LOH was more frequent in FTC than in follicular adenoma or papillary thyroid carcinoma. In FTC, rates of LOH on 3p (86%), 17p (72%), and 10q (57%) were higher than the average rate of LOH (33%; P < 0.05). Most frequently involved were 3p21-25 and 17p13.1-13.3, the sites for the VHL (3p25-26) and p53 (17p13.1) tumor suppressors. We, therefore, characterized these genes by dideoxy fingerprinting and DNA sequencing. Two FTC had mutations in p53, but only 1 of these exhibited LOH at 17p. No VHL gene mutations were found. Thus, neither p53 nor VHL genes play a significant role in the pathogenesis of differentiated thyroid cancer. LOH on 17p, but not on 3p or 10q, was correlated with mortality. Accordingly, 3p and 10q LOH may represent early, and 17p LOH late, events in FTC development. The data suggest the presence of novel tumor suppressor genes on chromosomes 3p and 17p that may be important in the pathogenesis of FTC.

Primary thyroid lymphoma.

The clinical and pathologic spectrum of lymphoproliferative disorders affecting the thyroid is diverse and must be differentiated from benign thyroiditis and carcinoma. The clinical presentations include an enlarging neck mass, but patients may also present with symptoms of dysphagia, hoarseness and choking, or a cold thyroid nodule. The histopathologic interpretation requires adequate tissue sampling and proper pathologic interpretation. The recent delineation of new pathological entities such as low-grade malignant lymphoma of mucosa-associated lymphoid tissue (MALT) type has aided in the understanding of the clinical course and management of patients with lymphoma. Advances have been made in the clinical management and treatment of these disorders. Surgical resection of the thyroid mass is not routinely part of the management strategy. The management of low-grade lymphoproliferative disorders of MALT type may include radiation therapy, oral chlorambucil, or intravenous chemotherapy (cyclophosphamide, vincristine, and prednisone). The management of diffuse large B-cell lymphoma is combined-modality therapy with radiation and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy.

Development of hypercalcemic hyperparathyroidism after long-term phosphate supplementation in hypophosphatemic osteomalacia. Report of two cases.

Orally administered phosphate supplements are the mainstay of therapy for hypophosphatemic osteomalacia of diverse causes and are generally believed to be free from harmful side effects. Two cases are reported, however, in which long-term therapy (14 and 10 years, respectively) resulted in hypercalcemic hyperparathyroidism associated with surgically proved adenomatous hyperplasia. This complication occurred despite concomitant treatment with pharmacologic doses of vitamin D. Thus, long-term oral phosphate therapy can produce tertiary hyperparathyroidism in susceptible patients.

Results of subtotal parathyroidectomy in hemodialysis patients.

In 61 hemodialysis patients undergoing subtotal parathyroidectomy, there was a good correlation between the preoperative serum immunoreactive parathyroid hormone value (iPTH) and the weight of parathyroid tissue removed surgically (p less than or equal to 0.001). Postoperatively, iPTH decreased rapidly from an initial mean (+/- SD) of 2,928 +/- 1,600 muleq/ml and remained at 365 +/- 296 muleq/ml at last follow-up of patients still undergoing hemodialysis (normal, less than 50 muleq/ml). Of six patients who had recurrent hyperparathyroidism (10 percent of total), three required a second subtotal parathyroidectomy. Aluminum-related osteomalacia eventually developed in six patients with bone biopsy-proven hyperparathyroidism before parathyroidectomy. Nine patients with severe fracturing bone disease and hypercalcemia preoperatively but without clear evidence of hyperparathyroidism did not show a favorable response to subtotal parathyroidectomy (high mortality within 28 months, persistence of hypercalcemia, and symptomatic bone disease). Thus, subtotal parathyroidectomy can benefit patients with clearly established severe progressive hyperparathyroidism not responsive to medical therapy but is contraindicated in patients with low iPTH values and no bone biopsy evidence of severe hyperparathyroidism.

Survival after the diagnosis of hyperparathyroidism: a population-based study.

BACKGROUND: Reports of increased mortality from cardiovascular disease and malignancy in primary hyperparathyroidism have been based primarily on patients who have undergone parathyroidectomy. In order to assess the true impact of primary hyperthyroidism on mortality in the general population, we assessed survival in a large inception cohort of Rochester, Minnesota residents with primary hyperparathyroidism initially diagnosed over a 28-year span, the majority of whom were followed with uncomplicated disease. METHODS: All Rochester residents with primary hyperparathyroidism first recognized in 1965 to 1992 were identified through the Rochester Epidemiology Project medical records linkage system. Included as cases were patients with pathologic confirmation of hyperthyroidism, hypercalcemia with inappropriately elevated parathyroid hormone levels, or hypercalcemia for more than a year with no other cause. Survival was estimated using the Kaplan Meier product-limit method. The Cox proportional hazards model was used to determine associations, as relative hazards (RR) with 95% confidence intervals (CI), of various risk factors with time to death. RESULTS: During the study period, 435 cases of primary hyperparathyroidism were identified. Altogether, parathyroid surgery was performed on 126 patients (29%), with a mean delay between the initial elevated serum calcium level and surgery of 3.3 years. Patients who underwent surgery had higher maximum serum calcium levels than the patients who were observed (mean+/-SD, 11.3+/-0.7 versus 10.7+/-0.4 mg/dL, P <0.00 1), but their mean ages were similar (54+/-16 versus 56+/-17 years). Overall survival in the patients with primary hyperthyroidism was better than expected (P=0.02), but by age-adjusted multivariate analysis, higher maximal serum calcium level was an independent predictor of mortality (RR=1.3 per mg/dL; 95% CI: 1.1-1.6; P <0.02). CONCLUSION: Overall survival is not adversely affected among unselected patients with mild primary HPT in the community, although patients with more severe disease, as manifested by higher serum calcium levels, may have an increased risk of death.

Surgical aspects of hyperinsulinemic hypoglycemia.

To make a diagnosis of insulinoma, one must consider it. Neuroglycopenic symptoms are the most prominent and convincing, and the combination of hypoglycemia and endogenous hyperinsulinemia are diagnostic of insulinoma. A glucose level of approximately 40 mg/dL with a concomitant insulin level of 6 microU/mL, a C-peptide level exceeding 200 pmol/L, and a negative screening for sulfonylurea must be documented to confirm the diagnosis. Although in the author's experience, preoperative ultrasound is the best and often the only test performed in the patient undergoing a first-time operation, arteriography is perhaps the single most effective localization test performed on a nationwide basis. Expertly performed intraoperative ultrasonography assists in tumor localization and in delineating important related anatomy and has become virtually routine in the author's surgical practice. Insulinomas are typically benign, single, and small, and are generally firmer than surrounding normal pancreas. Extensive surgical exposure may be required to identify and safely remove the tumor. Enucleation is preferred by the author, but distal pancreatectomy for tumors in the body or tail is an excellent method as well. Tumors in the head of the pancreas are usually enucleated, and pancreatoduodenectomy is rarely performed. The most troublesome complication is a pancreatic leakage causing pseudocyst, abscess, or fistula. Except in MEN 1 syndrome, in which a more extensive resection is usually indicated, excision of a single benign insulinoma leads to long-term cure of the disease. The successful excision of an insulinoma will profoundly affect a patient's life.

Are concomitant surgical procedures acceptable in patients undergoing cervical exploration for primary hyperparathyroidism?

Cervical exploration for primary hyperparathyroidism is an extremely safe procedure with essentially no operative mortality or morbidity and with success rates approaching 98%. These results have encouraged experienced surgeons to perform other surgical procedures concomitantly with cervical exploration with use of the same general anesthetic agent. This retrospective study was performed to assess the safety and efficacy of this practice. At our institution, 117 patients underwent cervical exploration for primary hyperparathyroidism in combination with an additional surgical procedure, including breast (25), biliary (21), gynecologic (19), intra-abdominal (18), and cardiothoracic (6) operations. The mean operative time was 155 minutes, and the mean duration of hospitalization was 7.6 days. Postoperatively, 115 patients (98%) were normocalcemic. Nine complications (mostly minor), which occurred in eight patients, related primarily to the concomitant surgical procedure. No operative mortality occurred. If performed by experienced surgeons in carefully selected patients, cervical exploration for primary hyperparathyroidism in combination with another elective operation is safe and cost-effective.

Leiomyosarcoma of the stomach: determinants of long-term survival.

To determine factors associated with a favorable long-term prognosis in gastric leiomyosarcoma, we retrospectively reviewed the medical records of 93 Mayo Clinic patients with this biopsy-proven tumor diagnosed during the 25-year period from 1964 through 1988. Six patients who had Carney's triad (gastric epithelioid leiomyosarcoma, pulmonary chondroma, and functioning extra-adrenal paraganglioma) were excluded from data analysis. The other 87 patients participated in follow-up until death or for a median duration of 5.8 years for those who were alive at the conclusion of the study. The most common symptoms at the time of initial assessment were abdominal pain (51%), melena (36%), and weight loss (16%). Most often, the tumor was located in the greater curvature (25%), fundus (20%), or lesser curvature (16%) of the stomach. Two percent of patients had tumors at multiple sites. All 87 gastric leiomyosarcomas were histologically confirmed; 38% were grade 1, 37% were grade 2, and 25% were either grade 3 or grade 4. Metastatic involvement was noted in 15% of patients at the time of diagnosis. The 5- and 10-year survival rates were 45% and 34%, respectively, and the 5- and 10-year tumor recurrence rates were 57% and 65%, respectively. Variables that were associated with long-term survival were low histologic grade of the tumor, absence of metastatic lesions, and small tumor size (P < 0.01); variables such as site of the tumor, initial symptoms, age, and sex provided no significant additional prognostic information.